Ultrafine hard alloys are tool materials developed in recent years, and the production of hard alloy materials with high hardness, high wear resistance and high toughness is mainly based on materials of ultra-fine WC powder, with addition of an appropriate binder (such as Co) and a grain growth inhibitor. With higher performance than conventional hard alloys, they have shown increasingly wide application prospects in areas such as low-machinability tools of metal materials, microbits of electronics industry, precision moulds and medical dental drills. The preparation of ultrafine WC powder is divided into two categories according to whether the process of reduction carbonization thereof is continuous or not: (1) a two-step method of reduction carbonization, in which W powder is first prepared from a tungsten-containing precursor, then reacted with carbonaceous substance to form WC powder by carbonization. (2) a single-step method of reduction carbonization, in which a tungsten-containing precursor (such as WO3) is subject to direct reduction carbonization to form WC powder, and generally a tungsten precursor with a higher activity is required to be prepared. Now, in industrial production, a precursor mixture of ultrafine tungsten powder and charcoal powder is generally used to produce ultrafine tungsten carbide powder by carbonization at high temperature. In this method, however, the ultrafine tungsten powder has a large specific surface area with a high surface activity, thus a slight contact with air will cause spontaneous combustion, affecting the product quality and resulting in material loss.